Or maybe this wasn't a surprise to anyone and was already priced in, and then the final numbers were slightly better than the general consensus expectation? Could be that too.

But you're right, everyone who owns stock in Tesla is probably the member of a cult, no need to think any harder about it.

TSLA is in the S&P 500 index so large numbers of people doing index investing own shares of it without thinking hard about its individual performance.

Yes but are those the marginal buyers and sellers that drive price movements? Most people in index funds are probably not flitting in and out of index positions at anything approaching even medium frequency.

Index investing doesn't steer price, it simply follows it.

"This is it." https://i.imgur.com/Oq5clQh.png